JPS58118033A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the generation of curls when a magnetic layer film is formed, by controlling the working pressure when a ground layer is coated with vapor phase on a flexible substrate and then a magnetic layer is coated with vapor phase on the ground layer and defining the internal stresses as positive and negative codes adversely to each other between the ground layer and the magnetic layer. CONSTITUTION:A ground layer is coated on a nonmagnetic and flexible substrate by various types of vapor-phase coating processes. This ground layer generally has about 50-5,000Angstrom thickness. A magnetic layer is formed on the ground layer. In this case, a sputtering process is applied in terms of the medium characteristics and the advantage of production. For the internal stress of both layers, the coating is performed on a rigid substrate with the same conditions as an actual case. In this case, the internal stress is measured and decided so that it shows the positive and negative codes adversely to each other between both layers. As a result, the generation of curls can be reduced. In particular, the curls can be virtually eliminated if both layers have positive and negative codes adversely to each other and at the same time the production of the absolute value and the film thickness of one layer is equivalent to about 50-150% product of the other layer.

Description

[Detailed description of the invention] ■ Background of the invention IA technology field The present invention relates to a method of manufacturing a magnetic recording medium.

More specifically, the present invention relates to an improvement in a method for manufacturing a continuous thin film magnetic recording medium.

rB Prior Art In recent years, continuous thin film magnetic recording media in which a magnetic layer is a metal magnetic thin film have attracted attention using vapor phase deposition methods such as vacuum evaporation, sputtering, and ion routing.

However, in such media, when a thin magnetic layer is formed by vapor phase deposition on a flexible substrate made of a long polymer molded material, etc., curling occurs in the width direction of the media. This causes the tape to bend, resulting in poor frequency characteristics, poor running performance, and even so-called tape squealing, and in extreme cases, the inconvenience of not being able to wind the tape into the cassette half.

To explain this situation in more detail,
In the vapor deposition method, which is the most commonly used vapor phase deposition method, when forming a magnetic layer, curling occurs frequently in such a way that the magnetic layer is on the inside. In this case, this curl is thought to be due to the fact that the film is formed with shrinkage force rather than due to thermal deformation during deposition.

In order to eliminate such curling during vapor deposition, conventional methods have been to apply stress after the magnetic layer has been deposited to cause a type of crack in the magnetic layer, or to perform heat treatment to shrink the substrate side. I'm doing it. However, none of these methods can prevent curling during film formation (and has many drawbacks in terms of productivity and other aspects).

Note that curling during film formation is a very serious problem even when using other deposition methods other than vapor deposition, such as sputter linking and ion V-ding, and a sufficient preventive measure has not yet been realized.

(2) Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and its main purpose is to provide a method that can prevent curling during the formation of a magnetic layer.

As a result of in-depth research for this purpose, the present inventors have found that the internal stress of the thin film that occurs during deposition and desorption can be controlled by gas phase deposition conditions, especially the operating pressure of argon gas, etc. Then, when depositing an underlayer on a flexible substrate in a vapor phase and depositing a magnetic layer on this underlayer in a vapor phase, the internal stress of both thin films can be easily reduced by controlling the operating pressure in both. The present inventors have discovered that curls can be eliminated as desired when the curl is tightened, leading to the present invention.

That is, in the present invention, when an underlayer is deposited on a flexible substrate in a vapor phase and a magnetic layer is deposited on the underlayer in a vapor phase, the above-mentioned underlayer j- and the magnetic layer are deposited in a vapor phase. This method of manufacturing a magnetic recording medium is characterized in that the operating pressure at this time is controlled so that the internal stress of the underlayer and the internal stress of the magnetic layer have opposite signs.

■Specific structure of the invention The specific structure of the present invention will be explained in detail below.
The substrate used in the present invention is non-magnetic and flexible (i), and films of polymer moldings such as polyester, polyimide, polyamide, etc. are particularly suitable. In this case, the thickness can be arbitrary.

In the present invention, a base layer is coated on such a flexible substrate.

The base material must be non-magnetic (various metals such as aluminum, silver, copper, chromium, titanium, manganese, red sium, tin, lead, etc., or various alloys, Si,
Various metals such as Ge, 5I02At, 03
, 'I'i02, Bi2O3, MyF2, and other various compounds.

Moreover, two or more layers of these can also be laminated.

However, as described later, when the magnetic layer is made of Co-Ni-P or Co-P alloy layer, aluminum,
Preferably, it is chromium, titanium, magnesium, or an alloy thereof, particularly an aluminum alloy, a chromium alloy, a titanium alloy, or a magnesium alloy.

When using such an underlayer and forming a #film magnetic layer with the above composition on it, the mechanical strength is improved compared to when using other underlayers, and it is easier to apply a load. The subsequent residual elongation becomes extremely small. In addition, when the base layer is not formed, when measuring the B-11 loop,
Its shape changes over the direction of continuous deposition, often resulting in two or more inflection points on the demagnetization curve of the BH loop,
The inconvenience of having to wait too long to decide on the old bias is also greatly reduced.

In this case, the aluminum alloy may be any of various alloys whose main component is aluminum, but in particular,
At least one of Si, Cu, Mn%Zn, Cr and M2 is contained in an amount of 25 wt% or less, preferably 0.
It is suitable that it contains 1 to 25 wt%, more preferably 1 to 20 wt%.

Further, as the chromium alloy, any of various alloys containing chromium as a main component may be used, but in particular, MOLTi, F
At least one of e%Co and Ni) is added to 5Q
It is suitable that the content is less than or equal to 0.1 Qwt%, preferably 0.1 to 5 Qwt%, and more preferably 1 to 5 Qwt%.

Further, the titanium alloy may be any of various alloys containing titanium as a main component, but especially At, Mn, V
, Cr and Fe; 4. Q
It is suitable that the content is less than or equal to wt%, preferably 0.1 to 4 Qwt%, more preferably 1 to 3 Qwt%.

In addition, the magnesium alloy may be any of various alloys whose main component is magnesium, but in particular A
01 or more of t, Zn, Z, r, Mn and rare earth elements at 3Qwt% or less, preferably from 01 to
30W [%, more preferably 1 to 20 wt%] is suitable.

Furthermore, the magnetic layer is Co-P or Co-N1-p.
Sputtering system #: When forming a film, among the above-mentioned underlayers, aluminum M, chromium alloy, titanium alloy, or magnesilano alloy is preferable.

In such a case, the coercive force is improved. In addition, the surface of the magnetic layer has good surface properties, improves head touch, and provides extremely high placement output. Overall, it exhibits extremely good characteristics, such as extremely little residual elongation and extremely little deformation of the BH loose.

Such a base layer is generally formed to have a thickness of about 50 to 5000 Å.

The underlayer can be formed by various vapor deposition methods such as vacuum deposition, sputtering, and ionoblating.

A magnetic layer is formed on such an underlayer.

The composition of the magnetic layer is Co-Ni yarn, Co-tte
system, Co-1to system, Co-P system, Co-Ni
-P type, Mn-At, and Itokiyu.

The thickness of the magnetic layer is not particularly limited, and may be varied depending on whether the magnetic recording medium performs analog recording or the intended use.

However, it is usually formed as a continuous thin film with a thickness of about 500A to several μm.

The method for forming the magnetic layer is selected from vapor deposition such as perpendicular incidence vapor deposition or oblique vapor deposition, sputtering, ion plating, etc. according to a vapor phase deposition method.

In this case, the magnetic layer is preferably formed by sputtering in view of medium characteristics and manufacturing advantages.

When a magnetic layer is formed by spuck linking, the composition thereof is preferably Co--P or Co->i--P based alloy.

The composition of the Co-P or Co-Ni-P alloy is XP (, 1μ, where X is Co or c.

too-y Y and Ni or a combination thereof with one or more other metal transfer metal elements. ) is preferable. In this case, Co/(Co-
1-Ni) Weight ratio X&''!, o or 35% or less is preferable. If it exceeds 35%,
This is because the magnetic properties th and the coercive force Hc decrease. In this case, the coercive force HCO point, x'b: 0~
More preferable results can be obtained if the amount is 30 L amount %, especially o to 28 N amount %.

On the other hand, y, that is, the P content, is preferably greater than 0 and 8% by weight or less. If it exceeds 8% by weight, the magnetic properties, especially the coercive force f(c) will decrease. In this case, the coercive force Hc.

For points, y is 1-8%, more preferably 1.5-7
% by weight gives preferable results.

In addition, in the above-mentioned Co-P or Co-N1-P alloy, other transition metal elements other than Co and Ni may be added, such as Fe, Cr, Mn, Mo, etc.
It is also possible for the above ingredients to be contained in an amount of 10% by weight or less of the total weight.

On the other hand, when sputtering is used, the sputtering method may be so-called RF sputtering or so-called DC sputtering, and the device configuration may be either two-pole or four-pole. For this purpose, so-called magnetron sputtering may be used, and in some cases, so-called reactive sputtering, which is performed while flowing a gas containing P, may also be used.

The target used is usually Co-N
A sintered body such as 1-P may be used.

On the other hand, as an ion source for impact ions, Ar, K
An inert gas such as r, Xe, etc. may be used. And these inert gases are 2X10 during operation.
It is preferable to maintain the pressure at -2 J'orr or higher.

This is because if the pressure is less than this, the magnetic properties of the obtained magnetic film, especially the coercive force He, will deteriorate.
On the other hand, if the operating pressure is increased, the sputtering rate will decrease. Therefore, the pressure during operation is generally f
It is preferable to set it to about iX1+]'' to 2X]0''l'orr.

In this case, in the present invention, the operating pressure for one deposition of the underlayer and the magnetic layer is controlled so that the internal stress of the magnetic layer and the internal stress of the underlayer have opposite signs. I will make it happen.

In this case, the internal stress of the surface layer is determined by depositing it on a rigid substrate under the same conditions as in reality and measuring the internal stress at that time so that the positive and negative values are reversed. Such internal stress is measured by using a rigid substrate with a known Young's modulus, adhering it as described above, and then measuring the warpage of the substrate by the so-called single-stick method.

In such a case, if the internal stresses in both layers were to have opposite signs, the curl would be significantly reduced. 5 of that
If it is about 0 to 150%, curls will almost disappear.

The internal stress between the magnetic layer and the underlayer can be reversed in polarity by controlling the film-forming pressure in vapor phase deposition.

That is, for example, when using RF sputtering,
At an operating force of 2 to 4 x 10 ” Torr, the internal stress in the plane direction becomes O. At operating pressures above this, the internal stress becomes negative and becomes a contraction force, and at operating pressures below this, the internal stress becomes O. becomes positive and becomes an extensional force.

Therefore, either the magnetic layer or the underlayer is 2×10
When forming the other film by sputtering at a pressure of 4×1.0 Torr or less,
Sputtering may be performed at the above pressure.

In addition, when using other sputtering, vapor deposition, and ion blating, the conditions for the internal stress in the plane direction to be O are as follows:
The operating pressure is almost the same as above, and this can be easily determined by experiment.

After this, if necessary, a protective layer is provided, a predetermined shape processing, etc. are performed, and a magnetic recording medium is manufactured.

The magnetic recording medium of the present invention manufactured in this way is useful as various magnetic data 1, flexible disks, etc. for performing analog or digital magnetic recording.

■Specific effects of the invention According to the invention, the curl is extremely small.

The present inventors conducted various experiments to confirm the effects of the present invention. An example is shown below.

Experimental Example 1 A continuous long polyethylene terephthalate film with a thickness of 6 μm was prepared as a flexible substrate.

For these four types of films, one has no base layer formed, and the other three have an At base layer of 2500A thickness formed by DC sputtering at the operating argon pressure shown in Table 1 below. did.

Next, a corresponding sintered body is used on top of these, and (C0
Q85NiQ5 )96 P4 composition magnetic layer, )tF
It was formed to a thickness of 3500 Å by sputtering at the operating argon pressure shown in Table 1 below.

Table 1 Operating argon pressure (Torr) Underlayer Magnetic layer Invention 5X10-3 7X10'' Comparison 1
7X10-2 comparison 2 3X10→
7X10” Comparison 3 7XlO-27XIQ −
2. Next, sputtering was performed on a slide glass under exactly the same conditions as the underlayer or magnetic layer sputter link conditions of each sample above, warpage was measured using the single-stick method, and the internal stress of each was measured. . The results are shown in Table 2. In this case, the negative sign of the internal stress represents a planar contraction force, and the positive sign represents a forward expansion force.

Table 2 Internal stress (dyne la!) Underlayer Magnetic layer Invention +8XlOI'-8; 109 comparison 1 -
-8X109 Comparison 2 =o -8XI09 Higeki 3 -8
Further, each of the above samples was slit to a width of 3.81 cm and a length of 70 m to prepare a microcassette tape MC-90.

For each of these microcassette tapes, the radius of curvature of the curl, the frequency characteristics of 315 Hz and 10 KHz at QdB input, and the number of cries during sexual intercourse for 45 minutes on one side were measured. The results are shown in Table 3 below.

Table 3 Curl frequency characteristics Tape curvature radius I QKHz / 315Hz Squeal (P++) (dB) (times) Invention
+50 Comparison 1 23 - 6 Comparison 2 2
0 +1 5 comparison 3 8 -1
0 10 From the results shown in Table 3, the effects of the present invention are clear.

Furthermore, for the sample of the present invention, the base layer aluminum was At-1,2Mn, At-4M in weight percent.
? -0.8Mn-Q, 3Si, Cr-25)
'e-] 5Mo, Ti-5At-3Mn
, and M Goo 10 At-0, IMnK were produced in exactly the same manner except for the above, and results completely equivalent to those described above were obtained.

On the other hand, when the coercive force 1-1c of each tape was measured, the values shown in Table 4 below were obtained. Note that Table 4 also shows the values without the base layer.

Next, after recording an 8K11z, OdB signal on each of these tapes, the tape speed for playback was set to 4.76°/
5ec), the output fluctuation (VU) of the C-90 tape was measured, and the magnitude of the output fluctuation mainly caused by variations in the thickness of the magnetic layer was evaluated. The results are shown in Table 4.

In addition, 14 KHz MOL was measured primarily to evaluate head touch caused by surface properties. The results are shown in Table 4.

Next, in order to evaluate the tape strength, each tape was cut into 1 m squares, one end of which was fixed and hung, and the other end was
A load of v was applied for 1 minute, and the elongation was measured thereafter. The residual elongation (%) measured in this way is shown in Table 4.
, Separately, in order to evaluate the adhesion of the magnetic layer, after recording on a valley cassette tape, it was heated at 25°C and a relative humidity of 60°C.
%, the track was run at 4.76 cm/Sec 500 times, and then played back to measure how many times the level decreased by 5 dB or less. The results are shown in Table 4.

Separately, we also measured the BH loops at 90 points every 80m for 11 volumes of data, and identified deformed points where the demagnetization curve of the BH loop had two or more inflection points. The number was measured. The results are shown in Table 4.

11 1985-118033 (6) From the results shown in Table 4, At, Cr, 'ri or M
The excellent effects of the 2-alloy base layer are obvious.

Experimental Example 2 Various samples were prepared as shown in Table 5 below, and the results shown in Table 5 were obtained.

The results shown in Table 5 demonstrate the effects of various alloy underlayers according to the present invention.

In addition, each of these dimensions includes coercive force, output fluctuation rlJ,
] 4 KHz MOL, residual elongation, adhesion deterioration, and BH Rogue deformation all showed extremely good characteristics.

Experimental Example 3 Each drawing circle was prepared as shown in Table 6 below,
The results shown in Table 6 were obtained.

From the results shown in Table 6, the effects of the present invention are clear.

Agent Patent Attorney Akira Ishii - 04) Procedure ``Ir1i (properly written voluntarily) Commissioner of the Japan Patent Office Shima 1) Haruki Tono1, Indication of the case 1982 Patent Application No. 2120352, Name of the invention Method for manufacturing magnetic recording media 3. Relationship with the case of the person making the amendment Patent applicant address: 13-1 Nihonbashi-chome, Chuo-ku, Tokyo Name (
(Name) (306) Tokyo Denki Kagaku 111i Co., Ltd. Representative: Fukujibe Sakuno 4, Agent: 104 Address: 2-15-14 Tsukiji, Chuo-ku, Tokyo Specification 6, Contents of amendment

Claims (1)

[Claims] When depositing a base layer on a flexible substrate in a vapor phase and depositing a magnetic layer on the base layer in a vapor phase, controlling the operating pressure during vapor phase deposition between the base layer and the magnetic layer. A method of manufacturing a magnetic recording medium, characterized in that the internal stress of the underlayer and the internal stress of the magnetic layer have opposite signs.